Haha. Yeah I disagree with their first "myth". Extremely fast weight loss reveals an unsustainable diet. That means ur likely starving urself and not creating sustainable habits. If the diet isnt sustainable, then that also implies that you'll eventually go back to something that is. Starvation always gears the body to store fat and burn muscle tissue to lower BMR requires as a survival technique. Its this type of fast, unsustainable weight loss that creates the term "yo-yo dieting" and is regularly taken advantage of by bodybuilders the get that "rebound growth" right after hard dieting for a show.